Flexible stay-bolt.



B. E. D. STAFFORD 6I E. I. DODDS.

FLEXIBLE STAY BOLT.

' APPLICATION FILED MAR.27. |915.

1,201,988. Patented OCI. 17,19I6.

NIIIIIII WI NESSES NVENTORS ZM./ Y @5A #www l Anm@ BENJAMIN E. D. STAFFORD AND ETI-IAN I. DODDS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS T0 FLANNERY BOLT COMPANY, OF PITTSBURGH, PENNSYLVANIA.'k

FLEXIBLE STAY-BOLT.

Speceation of Letters Patent.

Patented Oct. 17, 1916.

Application filed March 27, 1915. Serial No. 17,521.

To all whom 'it may concern.' j

Be it known that we, BENJAMIN E. D.

STAFFORD and ETHAN I. Donns, citizens ofv the United States, and residents of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements inA Flexible Stay Bolts; and we do hereby declare the following tobe a full, clear, and exact description of the inventio-n, such'as will enable others skilled in theJ art to which it appertains to make and use the same.

Our invention relates to an improvement in stay bolts for boilers, the object being to provide a yielding coupling for one end of the bolt, whereby ythe latter will be free to follow the movements of the ireibox sheet of the boiler without buckling or unduly straining either of the sheets, thus equalizing the stresses on both sheets.

A. further object is to so lconstruct thef bearing for the bolt head as to prevent scale from getting between the bolt-and the part of the bearing directly supporting the bolt head.

With these objects in view our invention consists in the parts and combination of the outer sheet and providedinternally with the flat, annular, inwardly projecting seat. 5,

and at its inner end with the curved or inclined seat 6, the seat 5 forming a support for theouter enlarged end S of the bushing 7 and the curved seat 6 forming a rest for the inner end 9 of said bushing. This bushing 'is cylindrical in shape and hollow, for the passage of the bolt through the same, and the portion thereof between its ends is luted circumferentially as shown, so as to act as a spring which will yield or give under longitudinal or lateral stresses to which the bolt may be subjected.

The bushing is provided at its outer end with a curved seat l0 in which the head 3 of the bolt l normally rests, and the inner end of the said bushing is constructed to bear against a shoulderjll formed on the bolt, and extending ycompletely around theV same.-V In the present instance this shoulder 11 is inclined, and the linner-end of the bushing is similarly shaped so as to make a close lit with the bolt to prevent the passage of any scale lup into the space between the bushing and bolt, and as the enlarged end 8 of the bushing makesV a close t with the seat '5 in 'ra sn'rES oFFicE.

the sleeve, no scale can pass around the .out-

or its seat l0 in the bushing. The bushing j 7 is held in place on its seats 5 and 6, by the cap l2 screwed ontoV the outer end Yof the sleeve, and provided with an inwardly projecting annularlip 13 which bears on the outer end ofthe bushingV and holds same rmly on its seat 8.

IVith this construction `it will be seen that in pulling stresses von the bolt, the head 3 thereof rests solidly on the unyielding seat l0 and acts as an ordinary flexible bolt of the' Tate type.

When the bolt elon'gates or is forced outwardly due to movements of the inner sheet, the shoulder 11 bearing against the inner end Vof the bushing compresses the latter sufficiently to compensate for the movement, and when the stress is relieved the spring action of the fluted bushing forces the bolt back to its normal position.

lower end of the lluted bushing is'connected Y to the bolt byscrew threads; the upper end of the bushing 'is flush with the sleeve, thus doing away with the long annular lip 18, and the head of the bolt is formed as an in-V tegral part of the bolt.

In Fig. 3, the lower end of the bushing is connected by threads with the bolt shank,.as v in Fig. 2, and the head of the bolt has a threaded engagement with the bolt as in Fig'l. n

In the construction shown in Fig. which is particularly adapted for the fire' sheet of a boiler, the sleeve la is screwed into the sheet and its outer edge upset against thevr outer face of the sheet so as to positively lock the sleeve against inward displacement and also form a tight joint.

' end, is luted so as to provide for the necessary spring action. The inner end of the bushing passes through the sleeve and is internally threaded for the attachment of the bolt la. With this construction it will be seen that Va pulling strain on the bolt simply draws the shoulder' 9*l onto its rigid unyielding seat 6, the shoulder 9a forming a head on which the bolt may turn so as to accommodate the latter to the movements of the sheets, Whereas an outward movement of the fire sheet, ora collapsing movement of the two sheets, causes the fluted part to give or yield and thus absorb the shock or strains.

The spring bushings or inner sleeves are preferably heat treated and cooled in oil so that the convoluted or spring section thereof will retain its elasticity when exposed to the high temperatures to which they are subjected in use. By increasing the number of convolutions, suiiicient elasticity may be produced to absorb or take care of all necessary longitudinal, lateral and vibratory movements to which the bolt may be subjected, due to elongation of the bolt itself, or to longitudinal and lateral movements of the bolt due to outward or lateral movement or buckling Vaction of the inner sheet, and provides in effect for universal movement of the end of the bolt within the coupling.

It is evident that many slight changes mightbe resorted to in the relative arrangement of parts shown and described without departing Vfrom the spirit and scope of our invention. Hence we would have it understood that we do not wish to confine ourselves to the exact construction shown and described, except as required by the scope of the appended claims.

I-Iaving fully described our invention what we claim as new and desire to secure by Letters-Patent, is :V- Y

l. In stay bolt construction, the combination of a sleeve, a spring bushing within the sleeve and secured at one end to the latter and a bolt engaging the free end of said bolt in one direction compresses the spring bushing.

2. In stay bolt construction, the combination of a sleeve, a spring bushing within the sleeve and supported at both ends within and by the sleeve, and a bolt engaging said bushing at one end, whereby longitudinal movement of the bolt toward the sleeve will compress thel bushing.

3. In stay bolt construction, the combination of a sleeve, a spring bushing within the sleeve, the said bushing' being secured at one end to the sleeve and loosely supported thereby at its other end, and a bolt engaging the free end of the bushing whereby the' latter may be compressed by a movement of the bolt in one direction.

Ll. In stay bolt construction, the combination of a sleeve and a spring bushing within the sleeve, the said bushing being detachably secured at one end to the sleeve and supported by said sleeve at its other end against expansion, and a bolt having engagement with the free end of the bushing whereby the latter may be compressed by a movement of the bolt in one direction.

5. In stay bolt construction, the combination of a sleeve and a spring bushing within the sleeve and secured at one end to the latter, and a bolt the head of which is mounted in a curved seat at the lixed end of the bushing and engaging the bushing atthe free y7. In stay bolt construction, the combina-r tion of a sleeve having two internal seats,

'a spring bushing the ends of which rest on said seats, a cap for locking the outer end of the bushing to the sleeve, and a bolt the head of which rests within a curved seat in the fixed end of the bushing and is provided with a shoulder bearing against the free end ofsaid bushing.

In testimony whereof, we have signed this specilication in the presence of two subscribing witnesses. i

i BENJAMIN E., D. STAFFORD.

ETHAN I. DODDS.

Witnesses:

F. I-I. ALLIsoN, EDWIN S. RYCE.

Copies'of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents.

Washington, D. C. 

